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Lab 22 Dissection Steps:
❏ Remove the skin on both halves of the specimen head, but leave muscles in place
wherever possible.
❏ Leave a rim of skin around the eyelids and the edge of the lips
❏ Remove the skin only from the base of the ear, leave the skin on the rest
of the pinna
❏ Identify the ​philtrum ​(if possible)
❏ Using the left half of your specimen head for identifying muscles, identify​ ​the ​platysma
m.​ ​ ​Carefully reflect the platysma m. rostrally (toward the nose).
❏ Identify the ​orbicularis
​
oris m., curving around the edges of the mouth. (Platysma m.
usually attaches to/integrates into the orbicularis oris m.)
❏
​ Identify the​​ ​ buccinator m. forming the foundation of the cheek; placing one finger
inside the left cheek and pushing outward will help you see the placement of this
muscle.
❏ Identify the ​levator nasolabialis m.
❏ Identify the ​superior & inferior palpebrae ​, the ​palpebral fissure​ (the opening between
the eyelids) as well as the ​medial & lateral palpebral commissures
❏ Identify the
​ ​orbicularis oculi m. ​surrounding the eyelid region.
❏ Identify the ​retractor anguli oculi lateralis m.
❏ Identify the ​conjunctival sac​. (This is the ‘cavity’ formed by palpebral and bulbar
conjunctiva.) Identify the ​palpebral conjunctiva​ and the ​bulbar conjunctiva
​ ❏ Identify the ​fornix (angle formed between palpebral and bulbar
conjunctiva)
❏ At the medial commissure,
​
attempt to identify
​
the​ lacrimal caruncle ​and ​lacrimal
​ puncta (dorsal and ventral) (which are the openings into the ​nasolacrimal duct; ​you
should also attempt to identify the other opening of the nasolacrimal duct inside the
nose)​.
❏ Identify the ​plica semilunaris (third eyelid)
❏ Identify the ​rostral auricular muscles​.​ ​Transect these muscles on the dorsal midline and
reflect them toward the ear.
❏ Attempt​ to identify the ​scutiform cartilage in the muscles rostral and medial to the
external ear
❏ Identify the ​caudal auricular muscles
​
❏ Identify the following parts of the oral cavity:​ vestibule ​and ​oral cavity proper
❏ Attempt to identify
​​
the ​parotid & zygomatic duct openings in the
vestibule; these can be very difficult to see in cadavers
❏ Examine the tongue and identify the ​root, body & apex.​ Identify the following
structures associated with the tongue:
❏ papillae: filliform, conical, fungiform, foliate, & vallate
❏ lingual frenulum
❏ Attempt to identify the ​lyssa on the ventral midline of the tongue, just
under the mucosa (this may be difficult to see in the cat)
❏ sublingual caruncle
❏ sublingual fold
❏ Incise the mucosa of the sublingual fold to identify
​ ​
the ​mandibular and major sublingual salivary
ducts
❏ On the lateral side of the head (left half), expose and identify the ​mandibular salivary
gland.
❏ Dissect rostral/medial to the mandibular salivary gland to identify the ​sublingual
salivary gland (monostomatic gland)
❏ At the base of the left ear identify the ​parotid salivary gland. ​Carefully dissect and
identify the ​parotid duct ​as it crosses the cheek/masseter muscle.
❏ Inside the mouth, examine the ​palate​. Look for the ​incisive papilla​ just caudal to the
incisor teeth.
​ ​ ❏ On the cut edge, attempt to identify a ​vomeronasal organ, but note that
this is typically not seen
❏ In the cat only, identify the ​buccal salivary gland
❏ On the cut edge of your head specimen, examine the region of the pharynx and identify
the following: ​oropharynx, nasopharynx, ​and ​laryngopharynx.
❏ In the oropharynx, identify the ​palatoglossal arch, ​the ​palatine tonsil,
and ​semilunar fold
❏ In the nasopharynx, identify the ​palatopharyngeal arch​ and the ​opening
of the auditory tube
❏ In the laryngopharynx, identify the ​pharyngoesphageal limen (border)
❏ Attempt to identify the following pharyngeal muscles: ​cricopharyngeus m.,
thyropharyngeus m., and ​hyopharyngeus m.